This application claims priority to an application entitled xe2x80x9cRoute Entry Guiding Device and Method in Navigation System Using Portable Terminalxe2x80x9d filed in the Korean Industrial Property Office on May 3, 2001 and assigned Serial No. 2001-24175, and to an application entitled xe2x80x9cRoute Entry Guiding Device and Method in Navigation System Using Portable Terminalxe2x80x9d filed in the Korean Industrial Property Office on Apr. 18, 2002 and assigned Serial No. 2002-21134, the contents of both of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates generally to a navigation system, and in particular, to a route entry guiding device and method in a navigation system using a portable terminal.
2. Description of the Related Art
Navigation systems or GPS (Global Positioning System) devices are commonly used in aircrafts, boats and other types of moving objects in order to track their positions and check their speeds.
A typical navigation system pinpoints the present position of a moving object on a displayed map using GPS information. It also provides information necessary for driving, such as the direction the moving object is pointing (heading), the present speed of the moving object, a route set by a driver before he starts, and an optimum route to his destination. This navigation system calculates the present position of the moving object based on GPS satellite signals including three-dimensional coordinate information (latitude, longitude and altitude) and provides map information including the present position to the driver visibly or audibly.
In general, a navigation device includes a GPS receiver for receiving GPS satellite signals and calculating pseudo-present position coordinates, a sensor unit having a gyro-sensor and a speed sensor for sensing the turning direction and speed of a vehicle, respectively, and a map data storage.
A navigation-enabled vehicle receives traffic information through an LCD (Liquid Crystal Display) and a speaker of a portable terminal. The traffic information contains traffic conditions or route guidance for guiding the driver to avoid congested roads. This is disclosed in Korean Patent Application No. 45851, entitled xe2x80x9cNavigation System Using Wireless Communication Network and Route Guidance Method Thereofxe2x80x9d and filed on Jul. 30, 2001 by the present applicant.
Conventional navigation services are limited only to route guidance when a driver travels in a route provided from a traffic information center or a CD-ROM (Compact Disk-Read Only Memory) and simply pinpoints the position of a vehicle on a digital map displayed on an LCD when off track from the route. In other words, conventional navigation systems provide route guidance information visibly or audibly only if the vehicle is on a predetermined road on the digital map, and provides no guidance to the driver when off track.
It is, therefore, an object of the present invention to provide a route entry guiding device and method for guiding a vehicle to an entry to a route in a navigation system using a portable terminal.
It is another object of the present invention to provide a route entry guiding device and method for guiding a vehicle to enter an optimum route defined on a digital map through a portable terminal without a graphic device to display the digital map.
The foregoing and other objects of the present invention are achieved by providing a route entry guidance device and method in a navigation system using a portable terminal. In the route guidance device, a navigation component of the portable terminal has a transmitter/receiver, a guiding mode determiner, a heading determiner, a projection direction determiner, and a route direction determiner. The transmitter/receiver transmits information including a departure point and a destination entered by a user to a traffic information center over a wireless network and receives optimum route data from the traffic information center over the wireless network in response to the transmitted information. The guiding mode determiner calculates the shortest distance to an optimum route indicated by the optimum route data and determines a guiding mode according to the shortest distance, if the optimum route data does not include a road where a vehicle is currently positioned. The heading determiner determines the heading of the vehicle with respect to true north using the latitude and longitude coordinates of two points measured by a GPS. The projection direction determiner calculates a relative angle of a projection direction to the optimum route with respect to the vehicle and determines the direction to the optimum route according to the calculated relative projection direction angle. The route direction determiner calculates a relative angle of the direction the optimum route runs with respect to the vehicle and determines a route direction according to the calculated relative route direction angle. According to the determined guiding mode, direction to the optimum route, and route direction, the vehicle is guided to the entry to the optimum route.